1. This Revision Petition is by the judgment-debtors in O.S. No. 211 of 1973, on the file of Sub Court, Sankari.

2. First respondent herein, as plaintiff filed the above suit for recovery of the amount due on a promissory note. The suit was decreed, and to recover the amount, Execution Petition No. 28 of 1985 was filed. Even though the Execution Petition was for recovery of the principal amount of Rs. 15,000/- and interest thereon, pending Execution Petition itself, petitioners paid Rs. 28,500/-, towards the decree debt. At that time, Execution Petition was pending before Sub Court, Salem. When a new Sub Court was constituted at Sankari, the Execution Petition was transferred to that Court and sale was held on 22-11-1985. On the date of sale, the balance amount payable to the decree-holder as per the Execution Petition was only Rs. 1,887/-. It is the case of the petitioners that they are entitled to the benefit of Act 40 of 1979 and, therefore, the petitioners are liable to pay only the actual principal amount of Rs. 15,000/- and Rs. 7,500/- as interest. Since they have already paid more than that amount, they were under the bona fide belief that they need not pay any am